Prosthetic tissue valve

ABSTRACT

A prosthetic tissue valve for aortic, pulmonary, mitral or tricuspid valve replacement is described herein. A sewing ring for use with the prosthetic tissue valve is also described. The valve can have a circumference that is a predetermined distance larger than the circumference of an annulus in a defective valve. The valve can be substantially planar in an unstressed position before attachment at the annulus and substantially non-planar upon attachment in a biased position at the annulus. Methods are provided for placing the valve as described herein in the biased position within the annulus of the defective valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 12/875,727, filed Sep. 3, 2010, which is a continuation-in-partof U.S. patent application Ser. No. 11/958,405, filed Dec. 18, 2007, nowabandoned, and U.S. patent application Ser. No. 11/958,407, filed Dec.18, 2007, now abandoned, and which also claims the benefit of the filingdate of U.S. Provisional Patent Application Ser. No. 61/295,503, filedJan. 15, 2010. Each of the above-referenced patent applications ishereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention generally relates to a prosthetic tissue valve forreplacing defective aortic, pulmonary, mitral or tricuspid valves. Morespecifically, the invention relates to a prosthetic tissue valve that issubstantially planar prior to implantation in an annulus andsubstantially non-planar following implantation in an annulus.

BACKGROUND OF THE INVENTION

In general, two types of artificial heart valves are used to replacedefective heart valves: mechanical valves and tissue valves. Althoughimplantation of artificial heart valves has traditionally occurredthrough open heart surgery, research and experimentation are being doneto develop valves that can be placed in a patient percutaneously,thereby avoiding open heart surgery.

Implantation of mechanical valves, which are durable, requires openheart surgery, risks peri-valvular leakage on the outside of the valvebetween the valve and the attachment wall, and requires a lifetime ofadministration of anti-coagulants, which requires close (usuallybi-weekly) monitoring in order to avoid either bleeding orthrombotic/embolic stroke. Mechanical valves also risk development ofstenosis at the valve replacement site, and incur chronic hemolysis(damage to red blood cells by the mechanical action of the valve).

Tissue valves typically last from 10 to 15 years in less active andelderly adults and are of porcine or human origin. They fail because thetissue of the valve begins to wear, at least in part because the valvesare retrieved after already having undergone partial lifetimes of use.Tissue valves in younger people wear out more quickly due to the moreactive blood flow in younger people, which causes rapid calcificationand places great mechanical demands on the valves. The risk of death orserious complications from surgical valve replacement is typically from1% to 5% depending on the health of the patient and the skill of thesurgeon. Therefore, it is preferred that a valve only be replaced onetime.

Mechanical valves last longer in younger patients because the patientsare still growing. However, pediatric valve replacements areparticularly challenging because the patients frequently outgrow theimplanted mechanical valve and require surgical intervention to replacethe pediatric valve with a larger valve.

Progressive deterioration of a tissue valve can lead to stenosis, whichmanifests itself as an obstruction of forward flow through the valvewhen the valve is in its open position. More commonly, deterioration ofa valve produces tears in the valve leaflets that cause regurgitation,which manifests itself as a leakage in the valve when the valve is inits closed position.

Known synthetic valves, although configured to mimic native valves,never assimilate fully into the surrounding tissue followingimplantation. In addition, attachment of known synthetic valves isaccomplished using a ring that remains in a single plane followingimplantation, thereby risking perivalvular leakage in the same manner asthe attachments of mechanical valves.

The tricuspid valve separates the right atrium from the right ventricle,and the mitral valve separates the left atrium from the left ventricle.The annuluses in which these valves are mounted typically comprise densefibrous rings that are attached either directly or indirectly to theatrial and ventricular muscle fibers. In a valve replacement operation,the damaged leaflets are excised and the annulus is sculpted to receivea replacement valve. Ideally, the annulus presents relatively healthytissue which can be formed by a surgeon into a substantially uniformledge that projects into the opening created after a native valve isremoved. The time and spatial constraints imposed by surgery, however,often dictate that the shape of the resulting annulus is less thanperfect for attachment of a sewing ring. Moreover, the leaflets of thevalve and the annulus may be calcified, and complete annulardebridement, or removal of the hardened tissue, can result in a largeropening and a more gradually sloped annulus ledge for attachment of thesewing ring. In short, the contours of the resulting annulus vary widelyafter the natural valve has been excised.

Conventional placement of a valve is intra-annular, with a valve bodydeep within the narrowest portion of the annulus to enhance any sealeffected by the sewing ring/suture combination and reduce the chance ofperivalvular leakage. Surgeons report using at least 30 simple suturesor 20 mattress-type sutures to prevent leakage.

The implantation of a prosthetic heart valve, including mechanicalvalves and bioprosthetic valves (i.e., “tissue” valve), requires a greatdeal of skill and concentration given the delicate nature of the nativeheart tissue, the spatial constraints of the surgical field and thecriticality of achieving a secure and reliable implantation. It is ofequal importance that the valve have characteristics that promote a longvalve life and have minimal impact on the physiological makeup of theheart environment.

Given the uneven nature of the annuluses, the design of the sewing ringand the method by which the sewing ring is fixed into place are perhapsthe most crucial aspects of prosthetic heart valve implantation. Due tothe inability of conventional sewing rings to easily stretch, if theselected size of the sewing ring is even slightly too small, attachmentcan only be achieved by placing undue tension on the tissue and sutures.As a result, a great deal of care and accuracy by the surgeon is neededin the selection of a valve size that precisely matches the valveannulus of the patient. Unfortunately, standard sizing tools areprovided in increments based on an overall opening size, and may not beable to accurately measure a less than optimally formed annulus. Thesurgeon thus must select an approximate valve size.

Accordingly, there is a need in the art of valve replacement proceduresfor a valve having the benefits of a tissue valve and the longevity of amechanical valve, without the side effects or disadvantages of either.Surgical outcomes would also benefit greatly by an improved sewing ring,permitting improved tissue attachment in all valve replacements.

SUMMARY OF THE INVENTION

In one aspect, a valve disclosed herein is designed to replace a nativevalve such as the aortic, pulmonary, mitral, or tricuspid valves in theheart of a subject. In one aspect, the valve can have a plurality ofleaflets that extend generally inwardly relative to a valvecircumference toward a radial center point of the valve such that atleast a portion of each leaflet contacts its adjacent leaflets. Whenplaced on a flat surface in an unstressed position before attachment ofthe valve in the subject, the valve is substantially flat or planar andcan therefore, in a further aspect, be formed from a substantiallyplaner material. In one aspect, the valve can have a sewing ring towhich the leaflets are attached and the sewing ring can be attached tothe valvular annulus at the site of valve replacement. In variousaspects, it is contemplated that the sewing ring can be less than about5 mm wide, and more preferably less than about 1 mm wide, therebymaximizing the portion of the luminal space that is available for bloodflow.

In another aspect, the sewing ring and the leaflets of the valve can bemade of a biointegrating material such that, over time in the body, theleaflets develop material properties substantially similar to oridentical to the material properties of native tissue found in the bodyof the subject. In one aspect, the biointegrating material used to makethe sewing ring and the valve can be an extracellular matrix material.

Although theoretically any extracellular matrix material can be used forthis purpose, preferred extracellular matrix materials are exogenousmammalian extracellular matrices, such as those derived from porcine orbovine sources. In one aspect, the extracellular matrices can be derivedfrom such tissues as small intestine submucosa (SIS), stomach submucosa(SS), liver basement membrane (LBM), urinary bladder submucosa (UBS),and in general any other sources of extracellular matrix material thatare retrievable from a mammal. The advantage of using the extracellularmatrix materials from mammalian sources is that these materials areknown to regenerate tissue at the site where they are placed in a humanor other mammal. In use, the extracellular matrix material of the sewingring and the valve can be in communication with the circulation of asubject and can develop into human tissue after about 3 to 6 months inthe subject's body. Thus, the regenerated tissue will be like new tissuewith the coordinate lifespan of new tissue, and will not need to bereplaced. In addition, with pediatric patients, the leaflet tissue cangrow with the patient and expand as the patient's heart tissue grows toadult proportions, thus eliminating the risk of needing a second orsubsequent surgery to replace the valve or the sewing ring.

In one aspect, the circumference of the valve can be defined by thesewing ring. In this aspect, the circumference of an outer portion ofthe sewing ring is formed to be larger than the circumference of theannulus of the valve lumen where the replacement is to occur. In oneaspect, the circumference of the valve can range from about 60 mm toabout 220 mm. The ratio of the operative valve circumference to theannular circumference can range from about 1.01:1 to about 3.00:1.Similarly, the operative valve diameter can be configured to be largerthan the diameter of the annulus, and the valve diameter can range fromabout 20 mm to about 70 mm. Optionally, the ratio of the operative valvediameter to the diameter of the annulus of the valve lumen can rangefrom about 1.01:1 to about 3.00:1.

In another aspect, although the claimed valve and sewing ring aregenerally planar in an unstressed position outside the body, uponattachment of the valve to the annulus in a biased position, they becomesubstantially non-planar. In this aspect, when the valve is attached tothe annulus in the biased position, the valve is configured to functionmuch like a native valve and work to control blood flow like a nativevalve does. Thus, using either intermittent or continuous attachmentpoints (such as suture), the edge of the valve is attached to theinterior wall of the annulus in a sinusoidal or wave-like pattern sothat each leaflet has substantially consistent high and low attachmentpoints that vary from the plane of the annulus. This attachment meansforms leaflets that are configured to form a valve in the annulus thatwill approximate or mimic the characteristics of a native tissue valvehaving native tissue leaflets with a rise and fall of leaflet tissueproviding for a substantially unidirectional flow of blood into a rightventricle, pulmonary artery, left ventricle, and aorta.

Preferred attachment means include using multiple sutures along thesewing ring, forming attachment of the sewing ring in an up and downconfiguration along the annular region to generally position the sewingring at the location of the annulus of the defective valve, anddirecting three-dimensional structural formation of the leaflets, whichstructure directs the leaflets to function similarly to the function ofnative leaflets in healthy native valves.

In operation, an edge portion of the valve can be wrapped around orotherwise attached to the sewing ring, if a sewing ring is used. In oneaspect, where the sewing ring is constructed of extracellular matrixmaterial, the extracellular matrix material can be rolled to formseveral layers in a tubular configuration forming the sewing ring byattachment of the two ends of the rolled material. Alternatively,additional ring-like pieces can be formed from extracellular matrixmaterial and can be laminated or otherwise coupled to the edge portionof the valve to form the sewing ring. As a still further alternative, acircular or linear strip of material having a width can be sewn, glued,or otherwise attached to itself, thereby forming a tear drop-like tubethat extends for a length and can either be attached at the two ends ofthe extracellular matrix material or extend for a circular distance in aring formation.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the preferred embodiments of the inventionwill become more apparent in the detailed description in which referenceis made to the appended drawings wherein:

FIG. 1 depicts a perspective view of a valve as described hereinpositioned relative to an annulus of the heart.

FIG. 2A depicts a top view of an exemplary planar valve withsubstantially triangular leaflets in an unstressed position beforeimplantation in an annulus in a non-planar configuration, as describedherein. FIG. 2B depicts a top view of an exemplary planar valve withsubstantially triangular leaflets and a sewing ring in an unstressedposition before implantation in an annulus in a non-planarconfiguration, as described herein.

FIG. 3A depicts a perspective view of the valve of FIG. 2B positionedrelative to an annulus of the heart. FIG. 3B depicts a perspective viewof the valve of FIG. 2B in a biased, non-planar position followingimplantation in the annulus of the heart, as described herein. FIG. 3Cdepicts a top view of the valve of FIG. 3B.

FIG. 4A depicts a top view of an exemplary planar valve withsubstantially rounded leaflets in an unstressed position beforeimplantation in an annulus in a non-planar configuration, as describedherein. FIG. 4B depicts a top view of an exemplary planar valve withsubstantially rounded leaflets and a sewing ring in an unstressedposition before implantation in an annulus in a non-planarconfiguration, as described herein.

FIG. 5A depicts a perspective view of the valve of FIG. 4B positionedrelative to an annulus of the heart. FIG. 5B depicts a perspective viewof the valve of FIG. 4B in a biased, non-planar position followingimplantation in the annulus of the heart, as described herein. FIG. 5Cdepicts a top view of the valve of FIG. 5B.

FIG. 6 depicts a top view of an exemplary planar valve withsubstantially triangular leaflets prior to folding of the outer edgeportion of the valve, as described herein.

FIG. 7 depicts a top view of an exemplary planar valve withsubstantially rounded leaflets prior to folding of the outer edgeportion of the valve, as described herein.

FIG. 8A depicts a cross-sectional view of an exemplary sewing ringrolled from a piece of extracellular material, as described herein. FIG.8B depicts a cross-sectional view of an exemplary sewing ring formedinto a tear drop shape, as described herein. FIG. 8C depicts across-sectional view of an exemplary sewing ring having a plurality oflaminated sheets of extracellular matrix material.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be understood more readily by reference to thefollowing detailed description, examples, drawings, and claims, andtheir previous and following description. However, before the presentdevices, systems, and/or methods are disclosed and described, it is tobe understood that this invention is not limited to the specificdevices, systems, and/or methods disclosed unless otherwise specified,as such can, of course, vary. It is also to be understood that theterminology used herein is for the purpose of describing particularaspects only and is not intended to be limiting.

As used in the specification and the appended claims, the singular forms“a,” “an” and “the” include plural referents unless the context clearlydictates otherwise. Thus, for example, reference to a “leaflet” caninclude two or more such leaflets unless the context indicatesotherwise.

Ranges may be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

As used herein, the terms “optional” or “optionally” mean that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances where said event or circumstanceoccurs and instances where it does not.

Without the use of such exclusive terminology, the term “comprising” inthe claims shall allow for the inclusion of any additionalelement—irrespective of whether a given number of elements areenumerated in the claim, or the addition of a feature could be regardedas transforming the nature of an element set forth in the claims. Exceptas specifically defined herein, all technical and scientific terms usedherein are to be given as broad a commonly understood meaning aspossible while maintaining claim validity.

Described herein are valves and replacement leaflets for controllingfluid flow in a lumen having an annulus. In one aspect, the valve issuitable for replacing an aortic, pulmonary, mitral, or tri-cuspid valvein the heart of a subject. In another aspect, the valve can comprise atleast one leaflet configured to selectively prevent undesiredregurgitation of blood flow therethrough the valve. For example, thevalve can comprise a single leaflet that is sized to prevent blood flowtherethrough the valve when the leaflet is selectively positioned in ablocking position. Alternatively, the valve can comprise a plurality ofleaflets. Optionally, the at least one leaflet can be attached to asewing ring. In a further aspect, a single leaflet as described hereincan be used as a replacement leaflet for controlling fluid flow throughan annulus. In a further aspect, the valve can have a circumference anda diameter that are larger than the circumference and diameter of theannulus.

In one aspect, as shown in FIGS. 6 and 7, it is contemplated that theleaflets of the valve 12 can be created from a substantially planarpiece of material, such as, for example and without limitation, asubstantially planar piece of extracellular matrix material as definedherein. In this aspect, the leaflets can be defined by cutting orstamping out selected portions of the planar piece of material usingconventional techniques. For example, as depicted in FIG. 6, theleaflets of the valve 12 can be cut from the substantially planar pieceof material in substantially triangular shapes. Alternatively, asdepicted in FIG. 7, the leaflets of the valve 12 can have substantiallyrounded shapes.

In another aspect, and with reference to FIGS. 6 and 7, prior topreparation of the valve 12 for implantation within the annulus 2, acircumference and, thus, an outer edge portion 15 of the valve can bedefined. In this aspect, the outer edge portion 15 of the valve 12 canhave a width E that ranges from about 3 mm to about 6 mm, and morepreferably is about 5 mm. It is contemplated that the outer edge portion15 of the valve can be rolled to create an attachment surface. In oneaspect, the attachment surface can be configured for direct attachmentthereto the annulus 2. Alternatively, the attachment surface can beconfigured for attachment thereto a sewing ring.

Optionally, in one exemplary aspect, as depicted in FIGS. 6 and 7,during the process of defining the leaflets and outer edge portion, anuncut portion 17 along the operative circumference of the valve 12 canalso be defined. In this aspect, the uncut portion 17 can have asubstantially consistent width U along the operative circumference ofthe valve 12. Where an uncut portion 17 is defined in the valve 12, itis contemplated that the width U of the uncut portion can range fromabout 1 mm to about 6 mm, and more preferably from about 4 mm to about 5mm.

FIGS. 2A and 4A each depict an exemplary valve 12 as it appears after ithas been prepared for implantation (after the outer edge of the valvehas been rolled up) but before attachment to the annulus 2. Moreparticularly, FIG. 2A depicts an exemplary valve 12 having substantiallytriangular leaflets, while FIG. 4A depicts an exemplary valve havingsubstantially rounded leaflets. It is contemplated that thecircumference of the valve 12 following the rolling of the outer edgeportion 15 of the valve can correspond to an operative circumference ofthe valve. Similarly, the diameter of the valve 12 following the rollingof the outer edge portion 15 of the valve can correspond to an operativediameter (d_(v)) of the valve. As used herein, the operative diameter(d_(v)) of the valve 12 corresponds to the portion of the valve that isconfigured to span across the annulus 2 after attachment of the valvethereto the annulus. Thus, as used herein, the operative diameter(d_(v)) does not factor in outer edge portion 15, which is rolled upprior to attachment of the valve 12 thereto the annulus 2.

In another aspect, the valve 12 can comprise at least one leaflet. Inthis aspect, the at least one leaflet can comprise a plurality ofleaflets. In an additional aspect, leaflets 28, 30, and 32 can havedistal end portions that extend inwardly relative to the circumferenceof the valve generally toward a radial center 20 of the valve.

Optionally, the valve 12 can comprise a sewing ring 40. In one aspect,the sewing ring 40 can be attached to the rolled up outer edge portion15 of the valve 12. In another aspect, before attachment to the annulus,the sewing ring 40 can be substantially semi-lunar or circular with aninner portion and an outer portion. In this aspect, the inner portion ofthe sewing ring can be attached to the valve, while the outer portion ofthe sewing ring 40 can define an operative circumference of the sewingring and, thus, the operative circumference of the valve 12. Similarly,the outer diameter of the sewing ring 40 can define the operativediameter of the sewing ring and, thus, the operative diameter (d_(v)) ofthe valve 12.

FIGS. 2B and 4B depict valve 12 and sewing ring 40 as they are beforeattachment to the annulus. More particularly, FIG. 2B depicts anexemplary valve 12 having substantially triangular leaflets and sewingring 40, while FIG. 4B depicts an exemplary valve having substantiallyrounded leaflets and sewing ring 40. In one aspect, the valve 12 cancomprise at least one leaflet. In this aspect, the at least one leafletcan comprise a plurality of leaflets. In one aspect, leaflets 28, 30,and 32 can have distal end portions that extend inwardly relative to theinner portion of the sewing ring 40 generally toward a radial center 20of the valve.

In one aspect, the operative circumference of the valve 12 can be largerthan the circumference of the annulus. In this aspect, when the annulusis located in a heart valve, including, for example and withoutlimitation, an aortic valve, a pulmonary valve, a tricuspid, or abicuspid (mitral) valve, the ratio of the operative circumference of thevalve to the circumference of the annulus can range from about 1.01:1 toabout 3.00:1, more preferably from about 1.40:1 to about 2.40:1, andmost preferably from about 1.70:1 to about 2.10:1. In addition to theratios serving as the endpoints of the ranges set forth above, thedisclosed ranges also include all ratios falling between the endpointratios. It is contemplated that, because the operative circumference ofthe valve 12 is greater than the circumference of the annulus 2, thevalve can form a substantially sinusoidal or wave-like pattern uponattachment to the annulus in the biased position. In another aspect, theoperative circumference of the valve can range from about 60 mm to about220 mm, more preferably from about 80 mm to about 190 mm, and mostpreferably from about 100 mm to about 140 mm. Optionally, it iscontemplated that the valves and sewing rings described herein can beprovided in a series of different circumferences, thereby permitting asurgeon to select an appropriately sized valve or sewing ring dependingon the dimensions of the annulus, which can be determined during asurgical procedure.

Similarly, in another aspect, and as shown in FIGS. 3A and 5A, theoperative diameter (d_(v)) of the valve 12 can be greater than thediameter (d_(a)) of the annulus 2. In this aspect, when the annulus islocated in a heart valve, including, for example and without limitation,an aortic valve, a pulmonary valve, a tricuspid, or a bicuspid (mitral)valve, the ratio of the operative diameter (d_(v)) of the valve to thediameter (d_(a)) of the annulus 2 can range from about 1.01:1 to about3.00:1, more preferably from about 1.40:1 to about 2.40:1, and mostpreferably from about 1.70:1 to about 2.10:1. In addition to the ratiosserving as the endpoints of the ranges set forth above, the disclosedranges also include all ratios falling between the endpoint ratios. Inanother aspect, the operative diameter (d_(v)) of the valve can rangefrom about 20 mm to about 70 mm, more preferably from about 25 mm toabout 60 mm, and most preferably from about 35 mm to about 45 mm.Optionally, it is contemplated that the valves and sewing ringsdescribed herein can be provided in a series of different diameters,thereby permitting a surgeon to select an appropriately sized valve orsewing ring depending on the dimensions of the annulus, which can bedetermined during a surgical procedure.

As shown in FIGS. 6-7, in one aspect, each leaflet can have an edgelength L corresponding to the total length of an inner edge of eachleaflet that extends inwardly relative to the operative circumference ofthe valve 12 generally toward a radial center 20 of the valve. In anadditional aspect, when the leaflets are substantially triangular asshown in FIG. 6, the edge length L of each leaflet can range from about10 mm to about 70 mm, more preferably from about 15 mm to about 60 mm,and most preferably from about 25 mm to about 45 mm. In this aspect, itis contemplated that the ratio between the edge length L of each leafletto the diameter (d_(a)) of the annulus 2 can range from about 0.5:1 toabout 3:1, and more preferably from about 1:1 to about 2:1. In additionto the ratios serving as the endpoints of the ranges set forth above,the disclosed ranges also include all ratios falling between theendpoint ratios. In another aspect, when the leaflets are substantiallyrounded as shown in FIG. 7, the edge length L of each leaflet can rangefrom about 15 mm to about 60 mm, more preferably from about 20 mm toabout 50 mm, and most preferably from about 25 mm to about 35 mm. Inthis aspect, it is contemplated that the ratio between the edge length Lof each leaflet to the diameter (d_(a)) of the annulus 2 can range fromabout 1:1 to about 2:1, and more preferably from about 1.20:1 to about1.40:1. In addition to the ratios serving as the endpoints of the rangesset forth above, the disclosed ranges also include all ratios fallingbetween the endpoint ratios.

In an additional aspect, and as shown in FIGS. 6-7, each leaflet canhave a height H. In this aspect, it is contemplated that each leafletcan have an apex corresponding to the point along edge length L of eachleaflet that is farthest from the operative circumference of the valve12, and the height H of each leaflet can correspond to the distancebetween the apex of each leaflet and the operative circumference of thevalve. In one aspect, when the leaflets are substantially triangular asshown in FIG. 6, the height H of each leaflet can range from about 10 mmto about 35 mm, more preferably from about 12 mm to about 30 mm, andmost preferably from about 17 mm to about 23 mm. In this aspect, it iscontemplated that the ratio between the height H of each leaflet to thediameter (d_(a)) of the annulus 2 can range from about 0.3:1 to about2:1, more preferably from about 0.5:1 to about 1.5:1, and mostpreferably from about 0.7:1 to about 1.1:1. In addition to the ratiosserving as the endpoints of the ranges set forth above, the disclosedranges also include all ratios falling between the endpoint ratios.Optionally, in this aspect, it is contemplated that the ratio betweenthe height H of each leaflet and the width U of the uncut portion 17 canrange from about 2:1 to about 7:1, and more preferably from about 4:1 toabout 5:1. In addition to the ratios serving as the endpoints of theranges set forth above, the disclosed ranges also include all ratiosfalling between the endpoint ratios. In another aspect, when theleaflets are substantially rounded as shown in FIG. 7, the height H ofeach leaflet 28, 30, 32 can range from about 5 mm to about 30 mm, morepreferably from about 10 mm to about 25 mm, and most preferably fromabout 12 mm to about 18 mm. In this aspect, it is contemplated that theratio between the height H of each leaflet to the diameter (d_(a)) ofthe annulus 2 can range from about 0.3:1 to about 1:1, more preferablyfrom about 0.4:1 to about 0.9:1, and most preferably from about 0.5:1 toabout 0.8:1. In addition to the ratios serving as the endpoints of theranges set forth above, the disclosed ranges also include all ratiosfalling between the endpoint ratios. Optionally, in this aspect, it iscontemplated that the ratio between the height H of each leaflet and thewidth U of the uncut portion 17 can range from about 1:1 to about 5:1,and more preferably from about 3:1 to about 4:1. In addition to theratios serving as the endpoints of the ranges set forth above, thedisclosed ranges also include all ratios falling between the endpointratios.

In a further aspect, attachment of the valve 12 can occur at a pluralityof attachment points on the operative circumference of the valve, suchas points 22, 24, and 26, as depicted in FIGS. 2A, 2B, and 3C for avalve having substantially triangular leaflets as described herein, andin FIGS. 4A, 4B, and 5C for a valve having substantially curved leafletsas described herein. Points 22, 24, and 26 can be radially aligned withpoints where adjacent leaflets 28, 30, and 32 contacted one anotherprior to attachment of the valve 12 thereto the interior surface of theannulus 2. In this aspect, for a valve 12 having a sewing ring 40,attachment of the valve can occur at a plurality of attachment points onthe outer portion of the sewing ring. As depicted in FIGS. 3B and 5B,the outer edge portion of the valve 12 can be attached to the interiorwall of the valve annulus 2 in a substantially sinusoidal or wave-likepattern. It is contemplated that the substantially sinusoidal patternformed by the valve 12 can promote substantially unidirectional bloodflow therethrough the valve. It is further contemplated that blood flowcan occur through the annulus 2 in an axial direction from points 14,16, and 18 to points 22, 24, and 26.

In one aspect, it is contemplated that the plurality of attachmentpoints can be substantially equally spaced along the circumference ofthe valve. In this aspect, for a valve 12 having a sewing ring 40, theplurality of attachment points can be substantially equally spaced alongthe outer portion of the sewing ring. In another aspect, the pluralityof attachment points can comprise at least three attachment points. In afurther aspect, the plurality of attachment points can comprise sixattachment points corresponding to points 22, 24, 26 and also points 14,16 and 18. It is contemplated that more points in between these equallyspaced points can also be used for attachment consistent with thewave-like pattern formed by the sewing ring when the valve is attachedin the biased position. In another aspect, the spacing between theattachment points of the plurality of attachment points can be minimizedsuch that the attachment points are placed substantially contiguouslyalong the outer portion of the sewing ring. Attachment can be, withoutlimitation, by suture using absorbable or permanent sutures. The exactknot tying technique can be selected at the preference of the operatingphysician.

As shown in FIGS. 3B and 5B, it is contemplated in one aspect, that thevalve 12, in the biased position, will be attached to the interiorsurface of the annulus such that the first portions 60 of the outer edgeportion of the valve that are adjacent to the base juncture of therespective adjoining leaflets of the valve are positioned substantiallyco-planar relative to each other or are generally the most upstreamportion of the outer edge portion of the valve. In this aspect, themedial portions 62 of the outer edge portion of the valve 12 (medialbetween the respective adjoining first portions) would extend downwardand be coupled to the interior surface of the annulus 2 at a positiondownstream of the first portions of the outer edge portion of the valve.In one aspect, the medial portions of the outer edge portion of thevalve can be substantially co-planar to each other downstream of thefirst portions of the outer edge portion of the valve.

In a further aspect, and with reference to FIGS. 3B-3C and 5B-5C, uponattachment of the valve thereto the annulus in the biased position, atleast a portion of leaflets 28, 30, and 32 can be superposed relative toat least a portion of adjacent leaflets. In this aspect, it iscontemplated that, in the biased position, at least a portion ofleaflets 28, 30, and 32 can be superposed relative to at least a portionof the other leaflets of the at least one leaflet, includingnon-adjacent leaflets. It is further contemplated that, in the biasedposition, at least a portion of leaflets 28, 30, and 32 can underlie atleast a portion of the adjacent leaflets of the at least one leaflet. Itis still further contemplated that, in the biased position, at least aportion of leaflets 28, 30, and 32 can overlie at least a portion of theadjacent leaflets of the at least one leaflet. In another aspect, it iscontemplated that the leaflets are configured such that, upon attachmentof the valve thereto the annulus in the biased position, the leafletscan selectively move to an overlapping or otherwise blocking positionthat is sufficient to selectively prevent undesired regurgitation bloodflow therethough the valve. In a further aspect, it is contemplated thatthe sinusoidal method of attaching the valve in the biased position canproduce a tight and conforming fit between the valve and the annulussuch that the likelihood of perivalvular leakage is reduced.

With reference to FIGS. 2A-3A and 4A-5A, it is contemplated that, in oneaspect, the valve 12 can be substantially planar in an unstressed orpre-insertion position before attachment to an interior surface of anannulus 2 of a valvular lumen. As illustrated in FIGS. 3B-3C and 5B-5C,it is contemplated that the valve can be substantially non-planar uponattachment in a biased position at the annulus. In another aspect, thedistal end portions of the respective leaflets can be configured toensure adequate operational overlay with the other leaflets to preventundesired directional passage of blood therethough the valve when thevalve is attached to the annulus in the biased position. It is alsocontemplated that portions of the distal edges of the respectiveleaflets can partially overlap other respective leaflets or canotherwise be in contact with each other to effect the desireddirectional passage of blood therethough the valve. Although notspecifically indicated in FIGS. 3C and 5C, it is contemplated that theportion of each leaflet that overlies or underlies adjacent leaflets canbe curved in a manner consistent with the curvature of the remainder ofthe leaflet.

In one aspect, the valve 12, including the sewing ring 40 and theleaflets 28, 30, and 32, can comprise a biointegrating material. Inanother aspect, the biointegrating material can comprise anextracellular matrix material. In a further aspect, the extracellularmatrix material can comprise mammalian extracellular matrix materialthat is obtained from mammalian tissue sources. In one exemplaryembodiment, the sewing ring and the leaflets comprise mammalianextracellular matrix material.

Mammalian tissue sources are in general any tissue having anextracellular matrix that can be isolated from the mammal anddecellularized. Thus, for example, mammalian organs are tissue sources.For example and without limitation, the tissue sources can be anymammalian tissue, for example and without limitation, the smallintestine, large intestine, stomach, lung, liver, kidney, pancreas,placenta, heart, bladder, prostate, tissue surrounding growing enamel,tissue surrounding growing bone, fetal tissue from any mammalian organs,and the like.

The forms of the extracellular matrices that make up the extracellularmatrix material are, without limitation, generally particulates,liquids, gels, pastes, emulsions, or suspensions. Liquid extracellularmatrices are generally thin emulsions or suspensions that are injectableand fluid. Suspension, emulsion or gel extracellular matrices can besubstantially thicker and have more body and substance than liquids, butsuspensions, emulsions or gels can also be injected if they are not toothick. Extracellular matrices in the form of pastes or near-solid gelsor plugs are more concentrated than liquids or injectable emulsions.Particulate extracellular matrices are powders that are formed from alyophilized sheet of extracellular matrix material that is broken upinto fine powder or particulate. Particulates can be used dry as apowder. Particulate extracellular matrices can also be reconstituted ina suitable buffer such as saline to transition into a liquid orsemi-solid form.

Extracellular matrix material can be obtained from the tissues ofmammals by processes such as described in U.S. Pat. No. 5,554,389, U.S.Pat. No. 4,902,508, and U.S. Pat. No. 5,281,422, which are specificallyincorporated by reference in their entirety. Enamel matrices aredescribed in U.S. Pat. No. 7,033,611 and U.S. Patent Publication No.2005/0043216, which are specifically incorporated by reference in theirentirety. For example, the urinary bladder submucosa (UBS) is anextracellular matrix that has the tunica mucosa (which includes thetransitional epithelial layer and the tunica propria), a submucosallayer, three layers of muscularis, and the adventitia (a looseconnective tissue layer). This general configuration is true also forsmall intestine submucosa (SIS) and stomach submucosa (SS). However, itis contemplated that any configuration of extracellular matrix tissuelayers, including, for example and without limitation, epithelialbasement membrane, tunica propria, stratum compactum, lamina muscularismucosa, tunica submucosa, tunica muscularis, and tunica serosa, can beused to produce the extracellular matrix material.

Other sources of extracellular matrix material include tissues such asthe liver and pancreas, which have an additional tissue layer called abasement membrane. For example, the extracellular matrix material cancomprise the liver basement membrane (LBM) of mammals prepared by theprocess described in U.S. Pat. No. 6,379,710, which is specificallyincorporated by reference in its entirety. Basement membranes generallydo not demonstrate the kind of tensile strength found in submucosa.However, other useful properties may be opportunistically employed fromthe extracellular matrices of such tissues as the liver, pancreas,placenta and lung tissues, all of which have either basement membranefor extracellular matrix or interstitial membrane (as with the lung).For example, pancreatic extracellular membranes support beta islet cellswhich are critical to pancreatic function. Also, for example, the liveris one tissue known to be able to regenerate itself and, therefore,special qualities may be present in the LBM that help facilitate thatprocess. The extracellular matrices surrounding developing tooth enameland developing bone also have particular advantages over other matricesin that they support the growth and differentiation of the hard tissuesof bone and enamel.

In some aspects, the extracellular matrix material can be from dermis.For example, AlloDerm®, produced by LifeCell Corporation, is anacellular tissue matrix which is produced from normal human skin usingprocessing techniques established to remove the epidermis and cellswithin the dermis without significantly altering the normal biochemistryand molecular architecture of the connective tissue matrix. Theresulting product is in a freeze-dried form allowing extended shelf lifeand ease of shipping without degradation or loss of the normal tissuematrix components. AlloDerm® can retain decorin, hyaluronic acid,chondroitin sulfates, nidogen, growth factors and other biochemicalproteins present in normal soft tissues. Additionally, AlloDerm® cancontain the basement membranes of vascular channels and the orientationof elastin and collagen fibers of the starting dermal tissue.

In some aspects, the extracellular matrix material can be obtained fromfascia. In some aspects, the extracellular matrix material can be fromparenchymal tissue. In other aspects, the extracellular matrix materialcan be from pericardium. In still other aspects, the extracellularmatrix material can be myocardial extracellular matrix. In additionalaspects, the extracellular matrix material can be from decellularizedheart tissue, produced, for example, by coronary artery perfusion withdetergents (Ott, H C, et al. Nat Med. 2008 February; 14(2):213-21).

In some aspects, the extracellular matrix material can comprise acollagen scaffold derived from a mammalian tissue or organ source. Thecollagen scaffold can in some aspects comprise the basement membrane ofthe mammalian tissue source.

In some aspects, the extracellular matrix material can be produced invitro. For example, the extracellular matrix material can be producedfrom a culture of mammalian cells. The extracellular matrix material canbe produced from proteins extracted from mammalian tissue/organs. Forexample, in some aspects, the extracellular matrix material comprises anartificial collagen scaffold synthesized from collagen extracted from amammalian tissue or organ source. Collagen from mammalian sources can beretrieved from matrix-containing tissues and used to form a matrixcomposition. Extracellular matrices can be synthesized from cellcultures as in the product manufactured by Matrigel™. In addition,dermal extracellular matrix material, subcutaneous extracellular matrixmaterial, large intestine extracellular matrix material, placentalextracellular matrix material, omentum extracellular matrix material,heart extracellular matrix material, and lung extracellular matrixmaterial, can be used, derived and preserved similarly as describedherein for the SIS, SS, LBM, and UBS materials. Other organ tissuesources of basement membrane for use in producing the extracellularmatrix material include the spleen, lymph nodes, salivary glands,prostate, pancreas and other secreting glands. In general, any tissue ofa mammal that has an extracellular matrix can be used for developing theextracellular matrix material.

Collagenous matrix can be selected from a variety of commerciallyavailable collagen matrices or can be prepared from a wide variety ofnatural sources of collagen. Collagenous matrix for use in accordancewith the disclosed compositions and methods can comprise highlyconserved collagens, glycoproteins, proteoglycans, andglycosaminoglycans in their natural configuration and naturalconcentration. Collagens can be from animal sources, from plant sources,or from synthetic sources, all of which are available and standard inthe art.

The extracellular matrix material can be made from a plurality ofmammalian tissue sources. Specifically, the extracellular matrixmaterial can be made from two mammalian tissue sources, three mammaliantissue sources, four mammalian tissue sources, five mammalian tissuesources, six mammalian tissue sources, and conceivably up to ten or moretissue sources. These tissue sources can be from the same mammal (forexample the same cow, the same pig, the same rodent, the same human,etc.), different mammalian animals of the same species, (e.g. cow 1 andcow 2, pig 1 and pig 2, rodent 1 and rodent 2, human 1 and human 2,etc.), or different species of mammals (for example LBM from a pig, SISfrom a cow, and UBS from a dog), all mixed together to form theextracellular matrix material).

The extracellular matrix material can also be a gel matrix combined witha particulate matrix, where the gel is applied to a space or cavity anddusted with powder-like particulates to increase the concentration ofmatrix at the surface of the cavity. The extracellular matrix materialcan be two or more liquid matrices (from different tissue sources)combined together. The extracellular matrix material can be two or moresuspension matrices (from different tissue sources) combined together.The extracellular matrix material can be two or more particulatematrices (from different tissue sources) combined together. Theparticulate matrices combined together can be applied to an annulus as aparticulate or as a rehydrated suspension, where saline or othersuitable buffer is applied to the particulate mixture and that hydratedcomposition is applied to the annulus in the individual being treated.The particulate can also be dusted onto a sheet of matrix before orafter placement at the annulus. The extracellular matrix material can bea liquid mixture of two or more extracellular matrices. With thisdusting embodiment, the liquid, gel, suspension or emulsion can be froma single mammalian tissue source, and dusted with a particulateextracellular matrix from either the same or a different mammaliantissue source. Accordingly, the suspension, emulsion, gel or liquid canbe SIS, and the particulate can be SIS, or the suspension, emulsion, gelor liquid can be SIS and the particulate can be SS, or LBM, or UBS. Thesuspension, emulsion, gel or liquid can be a mixture of SIS and LBM andthe particulate for dusting can be from SS. These examples are not meantto be exhaustive of the possible combinations of elements in theextracellular matrix material.

The extracellular matrix material can further include one or moreadditional components to aid in some aspect of the tissue regenerativeprocess or the generation of new tissue, however the biological activityis characterized. The additional component can be any component thatsomehow serves the extracellular matrix material and its purpose in themammalian body. Thus, the additional component can help to regeneratetissue, heal a wound, better recruit stem cells, manipulate the immuneenvironment in a beneficial way, therapeutically treat the localenvironment, or otherwise contribute to some aspect of the process forwhich the extracellular matrix material is being used.

In one aspect, the additional component can be one or more cells. Insome aspects, the additional component can be non-native cells, i.e.,cells that are heterologous to the mammalian ECM. In some aspects, theadditional component can be stem cells. A non-exhaustive list of stemcells include a human embryonic stem cell, a fetal cardiomyocyte, amyofibroblast, a mesenchymal stem cell, an autotransplanted expandedcardiomyocyte, an adipocyte, a totipotent cell, a pluripotent cell, ablood stem cell, a myoblast, an adult stem cell, a bone marrow cell, amesenchymal cell, an embryonic stem cell, a parenchymal cell, anepithelial cell, an endothelial cell, a mesothelial cell, a fibroblast,an osteoblast, a chondrocyte, an exogenous cell, an endogenous cell, astem cell, a hematopoietic stem cell, a pluripotent stem cell, a bonemarrow-derived progenitor cell, a progenitor cell, a myocardial cell, askeletal cell, a fetal cell, an embryonic cell, an undifferentiatedcell, a multi-potent progenitor cell, a unipotent progenitor cell, amonocyte, a cardiomyocyte, a cardiac myoblast, a skeletal myoblast, amacrophage, a capillary endothelial cell, a xenogenic cell, an allogeniccell, an adult stem cell, and a post-natal stem cell. In some aspects,the stem cells have the potential to differentiate into cardiac tissuecells. Thus, in some aspects, the stem cells can be pluripotent. Inother aspects, the stem cells can be angioblasts or hemangioblasts. Inadditional aspects, the stem cells can be myoblasts. The stem cellsdescribed herein can be derived and maintained using standard methodsfor stem cell culture.

In another aspect, the additional component can be a drug, including anyknown or newly discovered substance that can be administered to theheart of a subject. For example, the additional component can be anantithrombotic agent, including, for example, and without limitation,antiplatelet drugs, anticoagulants, and thrombolytic drugs. Exemplaryantiplatelet drugs include, for example and without limitation, Aspirin,Clopidogrel, Prasugrel, Ticlopidine, Cilostazol, Abciximab,Eptifibatide, Tirofiban, and Dipyridamole. Exemplary anticoagulantsinclude, for example and without limitation, Coumadins, Acenocoumarol,Phenprocoumon, Phenindione, Heparin, Low Molecular Weight Heparin,Fondaparinux, Idraparinux, Agratroban, Lepirudin, Bivalirudin, andDabigatran. Exemplary thrombolytic drugs include, for example andwithout limitation, Alteplase, Reteplase, Tenecteplase, Anistreplase,Streptokinase, and Urokinase.

In a further aspect, the additional component can be a protein. In thisaspect, the additional component can be an exogenous protein, such asthose normally found in mammalian ECM. Thus, it is contemplated that theadditional component can be, for example and without limitation, acollagen, a proteoglycan, a glycosaminoglycan (GAG) chain, aglycoprotein, a growth factor, a cytokine, a cell-surface associatedprotein, a cell adhesion molecule (CAM), an angiogenic growth factor, anendothelial ligand, a matrikine, a matrix metalloprotease, a cadherin,an immunoglobulin, a fibril collagen, a non-fibrillar collagen, abasement membrane collagen, a multiplexin, a small-leucine richproteoglycan, decorin, biglycan, a fibromodulin, keratocan, lumican,epiphycan, a heparan sulfate proteoglycan, perlecan, agrin, testican,syndecan, glypican, serglycin, selectin, a lectican, aggrecan, versican,nuerocan, brevican, cytoplasmic domain-44 (CD-44), macrophagestimulating factor, amyloid precursor protein, heparin, chondroitinsulfate B (dermatan sulfate), chondroitin sulfate A, heparan sulfate,hyaluronic acid, fibronectin (Fn), tenascin, elastin, fibrillin,laminin, nidogen/entactin, fibulin I, fibulin II, integrin, atransmembrane molecule, platelet derived growth factor (PDGF), epidermalgrowth factor (EGF), transforming growth factor alpha (TGF-alpha),transforming growth factor beta (TGF-β), fibroblast growth factor-2(FGF-2) (also called basic fibroblast growth factor (bFGF)),thrombospondin, osteopontin, angiotensin converting enzyme (ACE), or avascular epithelial growth factor (VEGF). Thus, in addition to one ormore extracellular matrix tissues, the disclosed extracellular matrixmaterial can comprise collagen I and III, elastin, laminin, CD44,hyaluronan, syndecan, bFGF, HGF, PDGF, VEGF, Fn, tenascin, heparin,heparan sulfate, chondroitin sulfate B, integrins, decorin, TGF-β, or acombination thereof.

It is contemplated that once the extracellular matrix material is in thebody of the subject, at least a portion of the extracellular matrixmaterial can integrate into the host tissue and develop substantiallythe same properties as proximate native material. Specifically, theextracellular matrix material can be in cellular communication with theblood supply of a subject. It is contemplated that at least 70% of theextracellular matrix material can fully integrate into the host tissue.More preferably, it is contemplated that at least 80% of theextracellular matrix material can fully integrate into the host tissue.Most preferably, it is contemplated that at least 90% of theextracellular matrix material can fully integrate into the host tissue.

It is contemplated that extracellular matrix material can be harvestedand processed as described in U.S. Pat. No. 5,554,389 (UBS), U.S. Pat.No. 6,099,567 (SS), and U.S. Pat. No. 6,379,710 (LBM), as well as U.S.Pat. No. 4,902,508, U.S. Pat. No. 4,956,178, U.S. Pat. No. 5,275,826,U.S. Pat. No. 5,516,533, U.S. Pat. No. 5,573,784, U.S. Pat. No.5,711,969, U.S. Pat. No. 5,755,791, U.S. Pat. No. 5,955,110, U.S. Pat.No. 5,968,096, U.S. Pat. No. 5,997,575, and U.S. Pat. No. 6,653,291(SIS), which are specifically incorporated by reference in theirentirety. In one aspect, it is contemplated that the valve 12 and sewingring 40 described herein can be stamped out of a sheet of extracellularmatrix material. For example, and without limitation, it is contemplatedthat the valve 12 as depicted in FIGS. 1A and 1B, and the sewing ring asdepicted in FIG. 3C, can be stamped out of a substantially planar sheetof extracellular matrix material. In an additional aspect, the valve 12and the sewing ring 40 can be continuous and can be formed or stampedout of a plane of laminate sheets of matrix material. In another aspect,the extracellular matrix material can be single sheets, multi-laminatesheets, or some other configuration of extracellular matrix that lendsitself to the formation of sheet-like leaflets. For example and withoutlimitation, the valve 12 and the sewing ring 40 can be stamped out of alarger laminate sheet of 2 ply, 3 ply, 4, ply, 5 ply, 6 ply, 7 ply, 8ply, 9 ply, and 10 ply extracellular matrix. It is further contemplatedthat the extracellular matrix material can be selectively formed at anappropriate width for the valve being replaced.

In a further aspect, the extracellular matrix material of the valve 12and sewing ring 40 can have a desired elastic modulus. For example, andwithout limitation, the desired elastic modulus of the extracellularmatrix material can range from about 5 to about 15, more preferably fromabout 7 to about 13, and most preferably from about 8 to about 12. It iscontemplated that the desired elastic modulus can be selected tosubstantially correspond to the elastic modulus of native tissuesurrounding the site of implantation of the valve, thereby improvingintegration of the valve into the host tissue. It is contemplated thatthe source of the extracellular matrix material, including, for exampleand without limitation, urinary bladder submucosa, small intestinesubmucosa, stomach submucosa, and liver basement membrane, can beselected depending on the desired elastic modulus.

In one aspect, FIG. 8A depicts a sewing ring 40 constructed from arolled piece of extracellular matrix material as described herein. Inthis aspect, the rolled piece of extracellular matrix material candefine a cross-sectional core 42. The sewing ring 40 can have a point ofattachment 44 where two ends of the sewing ring are attached to oneanother. In another aspect, and referring to FIG. 8B, the sewing ring 40can be defined by a tightly configured roll of extracellular matrixmaterial. In this aspect, the extracellular matrix material can befolded to itself and attached at point 46 with suture or glue or otherattachment means. The sewing ring 40 can have a cross-sectional core 48that illustrates the resulting tear-drop configuration of the sewingring when it is attached to itself. In another aspect, as shown in FIG.8C, the sewing ring 40 can be formed from a plurality of laminatedsheets 52 of extracellular matrix material. It is contemplated that theplurality of sheets 52 of extracellular matrix material can comprisemultiple types of extracellular matrix material, as described herein. Itis further contemplated that the sheets 52 of extracellular material canbe laminated together using any conventional biocompatible means forlamination of two structures. For example, it is contemplated that thesheets 52 of extracellular material can be laminated together using abiodegradable material.

In exemplary aspects, it is contemplated that the sewing ring 40 can beattached to the attachment surface defined by the outer edge portion 15of the valve 12 as described herein. It is further contemplated that theouter edge portion 15 of the valve 12 can be formed in the same manneras the sewing ring 40, as described herein, to thereby define theattachment surface, which can be configured for attachment to a sewingring or for direct attachment to the inner surface of the annulus 2.

In an additional aspect, it is contemplated that the sewing ring canhave a minimal width compared to the area defined by the annulus. Inthis aspect, the width of the sewing ring can be less than about 5 mm,and more preferably less than about 1 mm. It is still furthercontemplated that the tight fit between the sewing ring and the annulus,coupled with the minimal width of the sewing ring, can maximize theportion of the lumen available for accommodating blood flow followingattachment of the valve in the biased position.

It is contemplated that the extracellular matrix material of the sewingring can be used with the leaflets of a trileaflet valve or with othervalves such as pulmonary, aortic, mitral or tricuspid valves. The sewingring can be used with mechanical or tissue valves.

In addition to comprising extracellular matrix material, the sewing ring40 can further comprise metal, or a mixture of conventional metals oralloys. In one aspect, the sewing ring can also comprise a shape memoryactivated (SMA) material such as, for example and without limitation,Nitinol or other conventional SMA materials. It is contemplated that thesewing ring can be a synthetic or polymeric material, such as, forexample and without limitation, silicone, rubber, plastic, or the like.In one aspect, the sewing ring can be constructed like catheter tubing,with a woven support of metal wire embedded within the reinforcedplastic of the tubing. In another exemplary aspect, the sewing ring cancomprise an extracellular matrix material and a conventional polymericmaterial. In this aspect, it is contemplated that the extracellularmatrix material can be subjected to a conventional electrospinningprocess and then applied to the polymeric material to produce the sewingring.

In one aspect, it is contemplated that the sewing ring can comprise abiodegradable material. In this aspect, it is contemplated that thebiodegradable material can be configured to degrade followingsignificant integration of the extracellular matrix material into thehost tissue of the subject. More generally, it is contemplated that thesewing ring can be made of any material suitable for the purposeidentified in the definition of a sewing ring. It is furthercontemplated that the functionality of the sewing ring can be maintainedby ensuring that the sewing ring possesses sufficient flexibility topermit the larger circumference of the sewing ring to be placed into thesmaller circumference of the annulus in a non-planar attachmentconfiguration.

It is further contemplated that each configuration of the sewing ringimparts different advantages, and it is contemplated that differentvalves will be more or less appropriately suited for the differentvariations of sewing ring. For example, the sewing ring 40 of rolledextracellular matrix has a point where the ring is attached to itself.It is contemplated that this point of attachment would be considered aweak point in the sewing ring, and the ring needs to be attached toitself and the annulus with particular care and reinforcement so thatthe ring does not yield or break free at the point of attachment.Accordingly, it is contemplated that because sewing ring 40, whileunitary, is non-tubular, attachment of the ring to the annulus willrequire attendant care to that aspect of its configuration. In oneaspect, it is specifically contemplated that running sutures thatsurround the ring 40 will securely attach the ring to the annulus.Optionally, suturing through the ring itself can be used. This securingmethodology may be difficult due to the dense and strong nature of theextracellular matrix material. However, it is contemplated that suturescan be accomplished with conventional stitches or mattress stitchesdepending on the surgeon's assessment of the situation.

It is still further contemplated that attachment of the valve can beaccomplished percutaneously without open heart surgery. In use, thevalve can be guided to the site of replacement after the defective valvehas been removed, and the sewing ring can be systematically sutured orotherwise attached to the annular region in a biased position asdescribed herein, using a visualization technique enabling manipulationsin the body within the view of a camera that shows the manipulations tothe surgeon.

In further aspects, methods are provided for using the valves andreplacement leaflets as described herein to control fluid flow in alumen having an annulus. In one aspect, the methods comprise providingat least one replacement leaflet having the characteristics of theleaflets described herein. In another aspect, the methods comprisesecurely attaching the at least one replacement leaflet to the annulusin a desired position. It is contemplated that the at least one leafletcan comprise a single leaflet that is used to replace a single defectiveleaflet located therein an annulus in a heart of a subject with a bloodsupply. It is further contemplated that the at least one replacementleaflet can promote vascular development within the subject bypermitting cellular communication between the at least one leaflet andthe blood supply of the subject. Thus, it is further contemplated thatthe at least one replacement leaflet can effectively behave as a nativeleaflet after attachment in the desired position within the subject'sheart.

In another aspect, the method can comprise providing a valve asdescribed herein. In this aspect, the method can comprise securelyattaching the outer portion of the valve to the annulus in a biasedposition as described herein. Optionally, in an additional aspect, thevalve can comprise a sewing ring as described herein. In this aspect,the method can comprise securely attaching the outer portion of thesewing ring to the annulus such that the valve is in a biased positionas described herein.

In a further aspect, a kit having a valve as described herein can beassembled. Optionally, the kit can comprise a sewing ring as describedherein. Additionally, it is contemplated that the sewing rings asdescribed herein can be provided separately for attaching any number ofvalves.

Experimental Data in Support of Concept

In one long-term animal study, four clinically normal swine were used tostudy the effectiveness of porcine small intestine submucosa as cardiacpulmonary valve leaflets. Matheny, et al., Porcine Small IntestineSubmucosa as a Pulmonary Valve Leaflet Substitute, The Journal of HeartValve Disease 2000; 9:769-775. In this study, each swine had onepulmonary valve leaflet excised and replaced with a leaflet producedfrom a layer of porcine small intestine submucosa. The leaflets weresecured within the annulus using a suture line. The swine wereindividually sacrificed at 56, 63, 88, and 111 days followingimplantation of the leaflets.

The leaflet removed 63 days after implantation was securely attached tothe annulus along the entire suture line. Although one fenestration waspresent, complete organization of the leaflet was observed. The apicalportion of the leaflet consisted of mature and moderately dense fibrousconnective tissue, while the basal portion of the leaflet had less denseand mucinous tissue. Complete endothelialization of the leaflet wasobserved.

The leaflet removed 88 days after implantation was also securelyattached to the annulus along the entire suture line. No fenestrationswere present, and the basal portion of the leaflet was cellular andmature connective tissue. The apical portion of the leaflet was notablylarger in comparison to the leaflet removed 63 days after implantation.The apical portion formed a largely acellular nodule composed of serum,cellular debris, and leukocytes in a dense network of fibrin (anorganized thrombus). A layer of residual and acellular matrix wasobserved at the center of the thrombus. Endothelial cell coverage of theleaflet was continuous.

The leaflet removed 111 days after implantation was securely andcontinuously attached to the annulus along the entire suture linewithout evidence of thrombus. The leaflet was observed to possess grosscharacteristics similar to those of normal leaflet tissue. Specifically,the leaflet was observed to have histologically identifiable featuresand was composed of collagenous tissue containing indistinct layers ofviable cells. The histological organization of the leaflet wascomparable to the organization observed in the adjacent native leaflets.The surfaces of the leaflet were completely lined with endothelialcells.

Although several embodiments of the invention have been disclosed in theforegoing specification, it is understood by those skilled in the artthat many modifications and other embodiments of the invention will cometo mind to which the invention pertains, having the benefit of theteaching presented in the foregoing description and associated drawings.It is therefore understood that the invention is not limited to thespecific embodiments disclosed herein, and that many modifications andother embodiments of the invention are intended to be included withinthe scope of the invention. Moreover, although specific terms areemployed herein, they are used only in a generic and descriptive sense,and not for the purposes of limiting the described invention.

Various publications are referenced in this document. These publicationsin their entireties are hereby incorporated by reference into thisapplication in order to more fully describe the state of the art towhich the disclosed system and method pertains. The references disclosedare also individually and specifically incorporated by reference hereinfor the material contained in them that is discussed in the sentence inwhich the reference is relied upon.

What is claimed is:
 1. A valve for controlling fluid flow in a lumenhaving an annulus, the valve and the annulus each having acircumference, the valve comprising: a body having an outer edgeportion; and a plurality of leaflets disposed on the outer edge portionof the valve, wherein the valve is substantially planar in an unstressedposition, wherein the plurality of leaflets are substantially planar inthe unstressed position, wherein an operative diameter of the valve inthe unstressed position is configured to be larger than the diameter ofthe annulus, and wherein the outer edge portion of the body of the valveis configured for attachment to the annulus in a biased position,wherein, upon attachment of the valve to the annulus in the biasedposition, the outer edge portion of the body of the valve issubstantially non-planar, the plurality of leaflets are substantiallynon-planar, and at least a portion of at least one leaflet of theplurality of leaflets is superposed relative to at least a portion of atleast one of the adjacent leaflets of the plurality of leaflets, andwherein, in the biased position, a distal end of each leaflet of theplurality of leaflets extends radially inwardly generally toward acenter point in the valve, and wherein at least a portion of eachleaflet of the plurality of leaflets comprises extracellular matrixmaterial.
 2. The valve of claim 1, wherein the ratio of the operativediameter of the valve in the unstressed position to the diameter of theannulus is configured to range from about 1.01:1 to about 3.00:1.
 3. Thevalve of claim 1, wherein the ratio of the operative diameter of thevalve in the unstressed position to the diameter of the annulus isconfigured to range from about 1.70:1 to about 2.10:1.
 4. The valve ofclaim 1, wherein the operative diameter of the valve in the unstressedposition ranges from about 20 mm to about 70 mm.
 5. The valve of claim1, wherein the operative diameter of the valve in the unstressedposition ranges from about 35 mm to about 45 mm.
 6. The valve of claim1, wherein, upon attachment of the valve in the biased position, theouter edge portion of the valve is positioned along the circumference ofthe annulus in a substantially sinusoidal pattern.
 7. The valve of claim1, wherein each leaflet of the plurality of leaflets has an inner edgehaving an edge length corresponding to the total length of the inneredge of the leaflet that extends inwardly relative to the operativecircumference of the valve toward the center point of the valve, whereinthe edge length of each leaflet of the plurality of leaflets ranges fromabout 20 mm to about 50 mm.
 8. The valve of claim 7, wherein eachleaflet of the plurality of leaflets has an apex corresponding to thepoint along the inner edge of the leaflet that is farthest from theoperative circumference of the valve, wherein each leaflet of theplurality of leaflets has a height corresponding to the distance betweenthe apex of each leaflet and the operative circumference of the valve,and wherein the height of each leaflet of the plurality of leafletsranges from about 8 mm to about 25 mm.
 9. The valve of claim 1, wherein,upon configured attachment of the valve to the annulus in the biasedposition, at least a portion of the valve is configured forcommunication with circulation of a subject.
 10. The valve of claim 1,wherein the leaflets of the plurality of leaflets are spacedsubstantially equally along the outer edge portion of the valve.
 11. Thevalve of claim 1, wherein the outer edge portion of the body of thevalve is configured to attach to the annulus such that at least aportion of at least one leaflet of the plurality of leaflets underliesat least a portion of at least one of the adjacent leaflets of theplurality of leaflets.
 12. The valve of claim 1, wherein the outer edgeportion of the body of the valve is configured to attach to the annulussuch that at least a portion of at least one leaflet of the plurality ofleaflets overlies at least a portion of at least one of the adjacentleaflets of the plurality of leaflets.
 13. The valve of claim 1, whereinthe plurality of leaflets are configured to control blood flow throughan annulus in a heart.
 14. The valve of claim 1, wherein the outer edgeportion of the body of the valve defines an attachment surface, theattachment surface of the outer edge portion being configured for directattachment to the annulus.
 15. The valve of claim 14, wherein at least aportion of the outer edge portion is rolled up to define the attachmentsurface.
 16. The valve of claim 1, wherein each leaflet of the pluralityof leaflets has an inner edge having a substantially triangular shape.17. The valve of claim 1, wherein each leaflet of the plurality ofleaflets has an inner edge having a substantially rounded shape.
 18. Thevalve of claims 1, wherein each leaflet of the plurality of leaflets hasan inner edge, and wherein the inner edge of at least a portion of oneleaflet of the plurality of leaflets has a rounded shape.
 19. The valveof claims 1, wherein the inner edge of at least a portion of one leafletof the plurality of leaflets has a linear shape.
 20. The valve of claims18, wherein the inner edge of at least a portion of one leaflet of theplurality of leaflets has a linear shape.